Like I said, it depends where you fly.
In the US, South Africa, no - stay AVGAS.
In Europe, depends.
Everywhere else, go JET A! It's cheaper, and it's 'everywhere'.
SMA is MUCH better than Thielert (no gearbox as just one advantage).
But it is a very expensive upgrade, I would guess 120-130K EUR (based on the 80-90 they were asking for the 4 cyl). Those (very rough) prices as fully installed and without any credit from resell of old engine.